arch/powerpc/sysdev/xics/xics-common.c

   1 /*
   2  * Copyright 2011 IBM Corporation.
   3  *
   4  *  This program is free software; you can redistribute it and/or
   5  *  modify it under the terms of the GNU General Public License
   6  *  as published by the Free Software Foundation; either version
   7  *  2 of the License, or (at your option) any later version.
   8  *
   9  */
  10 #include <linux/types.h>
  11 #include <linux/threads.h>
  12 #include <linux/kernel.h>
  13 #include <linux/irq.h>
  14 #include <linux/debugfs.h>
  15 #include <linux/smp.h>
  16 #include <linux/interrupt.h>
  17 #include <linux/seq_file.h>
  18 #include <linux/init.h>
  19 #include <linux/cpu.h>
  20 #include <linux/of.h>
  21 #include <linux/slab.h>
  22 #include <linux/spinlock.h>
  23
  24 #include <asm/prom.h>
  25 #include <asm/io.h>
  26 #include <asm/smp.h>
  27 #include <asm/machdep.h>
  28 #include <asm/irq.h>
  29 #include <asm/errno.h>
  30 #include <asm/rtas.h>
  31 #include <asm/xics.h>
  32 #include <asm/firmware.h>
  33
  34 /* Globals common to all ICP/ICS implementations */
  35 const struct icp_ops    *icp_ops;
  36
  37 unsigned int xics_default_server                = 0xff;
  38 unsigned int xics_default_distrib_server        = 0;
  39 unsigned int xics_interrupt_server_size         = 8;
  40
  41 DEFINE_PER_CPU(struct xics_cppr, xics_cppr);
  42
  43 struct irq_domain *xics_host;
  44
  45 static LIST_HEAD(ics_list);
  46
  47 void xics_update_irq_servers(void)
  48 {
  49         int i, j;
  50         struct device_node *np;
  51         u32 ilen;
  52         const u32 *ireg;
  53         u32 hcpuid;
  54
  55         /* Find the server numbers for the boot cpu. */
  56         np = of_get_cpu_node(boot_cpuid, NULL);
  57         BUG_ON(!np);
  58
  59         hcpuid = get_hard_smp_processor_id(boot_cpuid);
  60         xics_default_server = xics_default_distrib_server = hcpuid;
  61
  62         pr_devel("xics: xics_default_server = 0x%x\n", xics_default_server);
  63
  64         ireg = of_get_property(np, "ibm,ppc-interrupt-gserver#s", &ilen);
  65         if (!ireg) {
  66                 of_node_put(np);
  67                 return;
  68         }
  69
  70         i = ilen / sizeof(int);
  71
  72         /* Global interrupt distribution server is specified in the last
  73          * entry of "ibm,ppc-interrupt-gserver#s" property. Get the last
  74          * entry fom this property for current boot cpu id and use it as
  75          * default distribution server
  76          */
  77         for (j = 0; j < i; j += 2) {
  78                 if (ireg[j] == hcpuid) {
  79                         xics_default_distrib_server = ireg[j+1];
  80                         break;
  81                 }
  82         }
  83         pr_devel("xics: xics_default_distrib_server = 0x%x\n",
  84                  xics_default_distrib_server);
  85         of_node_put(np);
  86 }
  87
  88 /* GIQ stuff, currently only supported on RTAS setups, will have
  89  * to be sorted properly for bare metal
  90  */
  91 void xics_set_cpu_giq(unsigned int gserver, unsigned int join)
  92 {
  93 #ifdef CONFIG_PPC_RTAS
  94         int index;
  95         int status;
  96
  97         if (!rtas_indicator_present(GLOBAL_INTERRUPT_QUEUE, NULL))
  98                 return;
  99
 100         index = (1UL << xics_interrupt_server_size) - 1 - gserver;
 101
 102         status = rtas_set_indicator_fast(GLOBAL_INTERRUPT_QUEUE, index, join);
 103
 104         WARN(status < 0, "set-indicator(%d, %d, %u) returned %d\n",
 105              GLOBAL_INTERRUPT_QUEUE, index, join, status);
 106 #endif
 107 }
 108
 109 void xics_setup_cpu(void)
 110 {
 111         icp_ops->set_priority(LOWEST_PRIORITY);
 112
 113         xics_set_cpu_giq(xics_default_distrib_server, 1);
 114 }
 115
 116 void xics_mask_unknown_vec(unsigned int vec)
 117 {
 118         struct ics *ics;
 119
 120         pr_err("Interrupt 0x%x (real) is invalid, disabling it.\n", vec);
 121
 122         list_for_each_entry(ics, &ics_list, link)
 123                 ics->mask_unknown(ics, vec);
 124 }
 125
 126
 127 #ifdef CONFIG_SMP
 128
 129 static void xics_request_ipi(void)
 130 {
 131         unsigned int ipi;
 132
 133         ipi = irq_create_mapping(xics_host, XICS_IPI);
 134         BUG_ON(ipi == NO_IRQ);
 135
 136         /*
 137          * IPIs are marked IRQF_PERCPU. The handler was set in map.
 138          */
 139         BUG_ON(request_irq(ipi, icp_ops->ipi_action,
 140                            IRQF_PERCPU | IRQF_NO_THREAD, "IPI", NULL));
 141 }
 142
 143 int __init xics_smp_probe(void)
 144 {
 145         /* Setup cause_ipi callback  based on which ICP is used */
 146         smp_ops->cause_ipi = icp_ops->cause_ipi;
 147
 148         /* Register all the IPIs */
 149         xics_request_ipi();
 150
 151         return cpumask_weight(cpu_possible_mask);
 152 }
 153
 154 #endif /* CONFIG_SMP */
 155
 156 void xics_teardown_cpu(void)
 157 {
 158         struct xics_cppr *os_cppr = &__get_cpu_var(xics_cppr);
 159
 160         /*
 161          * we have to reset the cppr index to 0 because we're
 162          * not going to return from the IPI
 163          */
 164         os_cppr->index = 0;
 165         icp_ops->set_priority(0);
 166         icp_ops->teardown_cpu();
 167 }
 168
 169 void xics_kexec_teardown_cpu(int secondary)
 170 {
 171         xics_teardown_cpu();
 172
 173         icp_ops->flush_ipi();
 174
 175         /*
 176          * Some machines need to have at least one cpu in the GIQ,
 177          * so leave the master cpu in the group.
 178          */
 179         if (secondary)
 180                 xics_set_cpu_giq(xics_default_distrib_server, 0);
 181 }
 182
 183
 184 #ifdef CONFIG_HOTPLUG_CPU
 185
 186 /* Interrupts are disabled. */
 187 void xics_migrate_irqs_away(void)
 188 {
 189         int cpu = smp_processor_id(), hw_cpu = hard_smp_processor_id();
 190         unsigned int irq, virq;
 191         struct irq_desc *desc;
 192
 193         /* If we used to be the default server, move to the new "boot_cpuid" */
 194         if (hw_cpu == xics_default_server)
 195                 xics_update_irq_servers();
 196
 197         /* Reject any interrupt that was queued to us... */
 198         icp_ops->set_priority(0);
 199
 200         /* Remove ourselves from the global interrupt queue */
 201         xics_set_cpu_giq(xics_default_distrib_server, 0);
 202
 203         /* Allow IPIs again... */
 204         icp_ops->set_priority(DEFAULT_PRIORITY);
 205
 206         for_each_irq_desc(virq, desc) {
 207                 struct irq_chip *chip;
 208                 long server;
 209                 unsigned long flags;
 210                 struct ics *ics;
 211
 212                 /* We can't set affinity on ISA interrupts */
 213                 if (virq < NUM_ISA_INTERRUPTS)
 214                         continue;
 215                 /* We only need to migrate enabled IRQS */
 216                 if (!desc->action)
 217                         continue;
 218                 if (desc->irq_data.domain != xics_host)
 219                         continue;
 220                 irq = desc->irq_data.hwirq;
 221                 /* We need to get IPIs still. */
 222                 if (irq == XICS_IPI || irq == XICS_IRQ_SPURIOUS)
 223                         continue;
 224                 chip = irq_desc_get_chip(desc);
 225                 if (!chip || !chip->irq_set_affinity)
 226                         continue;
 227
 228                 raw_spin_lock_irqsave(&desc->lock, flags);
 229
 230                 /* Locate interrupt server */
 231                 server = -1;
 232                 ics = irq_get_chip_data(virq);
 233                 if (ics)
 234                         server = ics->get_server(ics, irq);
 235                 if (server < 0) {
 236                         printk(KERN_ERR "%s: Can't find server for irq %d\n",
 237                                __func__, irq);
 238                         goto unlock;
 239                 }
 240
 241                 /* We only support delivery to all cpus or to one cpu.
 242                  * The irq has to be migrated only in the single cpu
 243                  * case.
 244                  */
 245                 if (server != hw_cpu)
 246                         goto unlock;
 247
 248                 /* This is expected during cpu offline. */
 249                 if (cpu_online(cpu))
 250                         pr_warning("IRQ %u affinity broken off cpu %u\n",
 251                                virq, cpu);
 252
 253                 /* Reset affinity to all cpus */
 254                 raw_spin_unlock_irqrestore(&desc->lock, flags);
 255                 irq_set_affinity(virq, cpu_all_mask);
 256                 continue;
 257 unlock:
 258                 raw_spin_unlock_irqrestore(&desc->lock, flags);
 259         }
 260 }
 261 #endif /* CONFIG_HOTPLUG_CPU */
 262
 263 #ifdef CONFIG_SMP
 264 /*
 265  * For the moment we only implement delivery to all cpus or one cpu.
 266  *
 267  * If the requested affinity is cpu_all_mask, we set global affinity.
 268  * If not we set it to the first cpu in the mask, even if multiple cpus
 269  * are set. This is so things like irqbalance (which set core and package
 270  * wide affinities) do the right thing.
 271  *
 272  * We need to fix this to implement support for the links
 273  */
 274 int xics_get_irq_server(unsigned int virq, const struct cpumask *cpumask,
 275                         unsigned int strict_check)
 276 {
 277
 278         if (!distribute_irqs)
 279                 return xics_default_server;
 280
 281         if (!cpumask_subset(cpu_possible_mask, cpumask)) {
 282                 int server = cpumask_first_and(cpu_online_mask, cpumask);
 283
 284                 if (server < nr_cpu_ids)
 285                         return get_hard_smp_processor_id(server);
 286
 287                 if (strict_check)
 288                         return -1;
 289         }
 290
 291         /*
 292          * Workaround issue with some versions of JS20 firmware that
 293          * deliver interrupts to cpus which haven't been started. This
 294          * happens when using the maxcpus= boot option.
 295          */
 296         if (cpumask_equal(cpu_online_mask, cpu_present_mask))
 297                 return xics_default_distrib_server;
 298
 299         return xics_default_server;
 300 }
 301 #endif /* CONFIG_SMP */
 302
 303 static int xics_host_match(struct irq_domain *h, struct device_node *node)
 304 {
 305         struct ics *ics;
 306
 307         list_for_each_entry(ics, &ics_list, link)
 308                 if (ics->host_match(ics, node))
 309                         return 1;
 310
 311         return 0;
 312 }
 313
 314 /* Dummies */
 315 static void xics_ipi_unmask(struct irq_data *d) { }
 316 static void xics_ipi_mask(struct irq_data *d) { }
 317
 318 static struct irq_chip xics_ipi_chip = {
 319         .name = "XICS",
 320         .irq_eoi = NULL, /* Patched at init time */
 321         .irq_mask = xics_ipi_mask,
 322         .irq_unmask = xics_ipi_unmask,
 323 };
 324
 325 static int xics_host_map(struct irq_domain *h, unsigned int virq,
 326                          irq_hw_number_t hw)
 327 {
 328         struct ics *ics;
 329
 330         pr_devel("xics: map virq %d, hwirq 0x%lx\n", virq, hw);
 331
 332         /* They aren't all level sensitive but we just don't really know */
 333         irq_set_status_flags(virq, IRQ_LEVEL);
 334
 335         /* Don't call into ICS for IPIs */
 336         if (hw == XICS_IPI) {
 337                 irq_set_chip_and_handler(virq, &xics_ipi_chip,
 338                                          handle_percpu_irq);
 339                 return 0;
 340         }
 341
 342         /* Let the ICS setup the chip data */
 343         list_for_each_entry(ics, &ics_list, link)
 344                 if (ics->map(ics, virq) == 0)
 345                         return 0;
 346
 347         return -EINVAL;
 348 }
 349
 350 static int xics_host_xlate(struct irq_domain *h, struct device_node *ct,
 351                            const u32 *intspec, unsigned int intsize,
 352                            irq_hw_number_t *out_hwirq, unsigned int *out_flags)
 353
 354 {
 355         /* Current xics implementation translates everything
 356          * to level. It is not technically right for MSIs but this
 357          * is irrelevant at this point. We might get smarter in the future
 358          */
 359         *out_hwirq = intspec[0];
 360         *out_flags = IRQ_TYPE_LEVEL_LOW;
 361
 362         return 0;
 363 }
 364
 365 static struct irq_domain_ops xics_host_ops = {
 366         .match = xics_host_match,
 367         .map = xics_host_map,
 368         .xlate = xics_host_xlate,
 369 };
 370
 371 static void __init xics_init_host(void)
 372 {
 373         xics_host = irq_domain_add_tree(NULL, &xics_host_ops, NULL);
 374         BUG_ON(xics_host == NULL);
 375         irq_set_default_host(xics_host);
 376 }
 377
 378 void __init xics_register_ics(struct ics *ics)
 379 {
 380         list_add(&ics->link, &ics_list);
 381 }
 382
 383 static void __init xics_get_server_size(void)
 384 {
 385         struct device_node *np;
 386         const u32 *isize;
 387
 388         /* We fetch the interrupt server size from the first ICS node
 389          * we find if any
 390          */
 391         np = of_find_compatible_node(NULL, NULL, "ibm,ppc-xics");
 392         if (!np)
 393                 return;
 394         isize = of_get_property(np, "ibm,interrupt-server#-size", NULL);
 395         if (!isize)
 396                 return;
 397         xics_interrupt_server_size = *isize;
 398         of_node_put(np);
 399 }
 400
 401 void __init xics_init(void)
 402 {
 403         int rc = -1;
 404
 405         /* Fist locate ICP */
 406         if (firmware_has_feature(FW_FEATURE_LPAR))
 407                 rc = icp_hv_init();
 408         if (rc < 0)
 409                 rc = icp_native_init();
 410         if (rc < 0) {
 411                 pr_warning("XICS: Cannot find a Presentation Controller !\n");
 412                 return;
 413         }
 414
 415         /* Copy get_irq callback over to ppc_md */
 416         ppc_md.get_irq = icp_ops->get_irq;
 417
 418         /* Patch up IPI chip EOI */
 419         xics_ipi_chip.irq_eoi = icp_ops->eoi;
 420
 421         /* Now locate ICS */
 422         rc = ics_rtas_init();
 423         if (rc < 0)
 424                 rc = ics_opal_init();
 425         if (rc < 0)
 426                 pr_warning("XICS: Cannot find a Source Controller !\n");
 427
 428         /* Initialize common bits */
 429         xics_get_server_size();
 430         xics_update_irq_servers();
 431         xics_init_host();
 432         xics_setup_cpu();
 433 }